Genetic influence of DPYD*9A polymorphism on plasma levels of 5-fluorouracil and subsequent toxicity after oral administration of capecitabine in colorectal cancer patients of South Indian origin

Ethnic Diversity of DPD Activity and the DPYD Gene: Review of the Literature

Pharmacogenomic screening can identify patients with gene variants that predispose them to the development of severe toxicity from fluoropyrimidine (FP) chemotherapy. Deficiency of the critical metabolic enzyme dihydropyrimidine dehydrogenase (DPD) leads to excessive toxicity on exposure to fluoropyrimidine chemotherapy. This can result in hospitalisation, intensive care admissions and even death. Upfront screening of the gene that encodes for DPD (DPYD) has recently been implemented in regions throughout Europe and the United Kingdom. Current screening evaluates DPYD variants that are well described within Caucasian patient populations and provides genotyped-guided dose adjustment recommendations based upon the presence of these variants. This article reviews the differences in DPYD gene variants within non-Caucasian populations compared to Caucasian populations, with regard to the implications for clinical tolerance of fluoropyrimidine chemotherapies and genotype guided dose adjustment guidelines.

A case-control study of a combination of single nucleotide polymorphisms and clinical parameters to predict clinically relevant toxicity associated with fluoropyrimidine and platinum-based chemotherapy in gastric cancer

Background

Fluoropyrimidine plus platinum chemotherapy remains the standard first line treatment for gastric cancer (GC). Guidelines exist for the clinical interpretation of four DPYD genotypes related to severe fluoropyrimidine toxicity within European populations. However, the frequency of these single nucleotide polymorphisms (SNPs) in the Latin American population is low (< 0.7%). No guidelines have been development for platinum. Herein, we present association between clinical factors and common SNPs in the development of grade 3–4 toxicity.

Methods

Retrospectively, 224 clinical records of GC patient were screened, of which 93 patients were incorporated into the study. Eleven SNPs with minor allelic frequency above 5% in GSTP1, ERCC2, ERCC1, TP53, UMPS, SHMT1, MTHFR, ABCC2 and DPYD were assessed. Association between patient clinical characteristics and toxicity was estimated using logistic regression models and classification algorithms.

Results

Reported grade ≤ 2 and 3–4 toxicities were 64.6% (61/93) and 34.4% (32/93) respectively. Selected DPYD SNPs were associated with higher toxicity (rs1801265; OR = 4.20; 95% CI = 1.70–10.95, p = 0.002), while others displayed a trend towards lower toxicity (rs1801159; OR = 0.45; 95% CI = 0.19–1.08; p = 0.071). Combination of paired SNPs demonstrated significant associations in DPYD (rs1801265), UMPS (rs1801019), ABCC2 (rs717620) and SHMT1 (rs1979277). Using multivariate logistic regression that combined age, sex, peri-operative chemotherapy, 5-FU regimen, the binary combination of the SNPs DPYD (rs1801265) + ABCC2 (rs717620), and DPYD (rs1801159) displayed the best predictive performance. A nomogram was constructed to assess the risk of developing overall toxicity.

Conclusion

Pending further validation, this model could predict chemotherapy associated toxicity and improve GC patient quality of life.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08745-0.